System for controlling gas supply to a gas burner of a patio heater

ABSTRACT

A patio heater gas control system ( 10 ), the system ( 10 ) comprising: a timing module ( 50 ) to set a predetermined amount of time for gas to be supplied to a gas burner of the patio heater ( 20 ); an electromechanical valve ( 60 ) to control the flow of gas from a gas tank to the gas burner; an oxygen depletion system ( 80 ) to automatically extinguish and shut off the gas burner if the oxygen level falls below a predetermined level; and a tilt switch ( 40 ) to automatically extinguish and shut off the gas burner if the patio heater ( 20 ) if it is tilted greater than a predetermined angle; wherein when the predetermined amount of time has not expired, a closed and complete electrical circuit causes the electromechanical valve ( 60 ) to open and allow gas to flow from the gas tank to the burner, and when the predetermined amount of time has expired, the timing module ( 50 ) opens the electrical circuit to cause the electromechanical valve ( 60 ) to close and prevent gas flowing from the gas tank to the gas burner.

TECHNICAL FIELD

The invention concerns a system for controlling gas supply to a gas burner of a patio heater.

BACKGROUND OF THE INVENTION

Patio heaters are used to provide heat and warmth to people in an outdoor environment such as a backyard, patio or courtyard. Patio heaters generally comprise a base to house a gas cylinder tank, an upright pole, a gas burner and a dome-shaped reflector mounted above the gas burner. A gas hose supplies gas from the tank to the gas burner through the upright pole. The reflector reflects heat downwards rather than allowing it to escape immediately upward.

To operate the patio heater, a control knob is rotated to the ignition position. The control knob is pushed down to ignite a pilot burner by an igniter. Then, the control knob is rotated to increase or decrease the amount of gas supplied to the gas burner to increase or decrease the temperature. When a patio heater is no longer required, the control knob must be rotated to the closed position, and the pilot burner is extinguished. In commercial use where multiple patio heaters are used for heating a large outdoor area, it may be time consuming to constantly monitor and remember to turn off each one. Also, if some have been forgotten to be turned off, gas is wasted as it is continually burned when heat is no longer required.

Accordingly, there is a desire to provide a simple, convenient and cost-effective system for minimising the wastage of gas burned by a patio heater when use of the patio heater is no longer required.

SUMMARY OF THE INVENTION

In a first preferred aspect, there is provided a patio heater gas control system, the system comprising:

-   -   a timing module to set a predetermined amount of time for gas to         be supplied to a gas burner of the patio heater;     -   an electromechanical valve to control the flow of gas from a gas         tank to the gas burner;     -   an oxygen depletion system (ODS) to automatically extinguish and         shut off the gas burner if the oxygen level falls below a         predetermined level; and     -   a tilt switch to automatically extinguish and shut off the gas         burner if the patio heater if it is tilted greater than a         predetermined angle;     -   wherein when the predetermined amount of time has not expired, a         closed and complete electrical circuit causes the         electromechanical valve to open and allow gas to flow from the         gas tank to the burner, and when the predetermined amount of         time has expired, the timing module opens the electrical circuit         to cause the electromechanical valve to close and prevent gas         flowing from the gas tank to the gas burner.

The system may further comprise a thermometer and a temperature control module to maintain a predetermined temperature.

The system may further comprise a remote control to reset the predetermined amount of time for timing module.

The timing module may be a mechanical or an electronic timer.

The electromechanical valve may be a solenoid valve.

The patio heater may comprise:

-   -   a base to house the gas tank,     -   an upright pole,     -   the gas burner,     -   a dome-shaped heat reflector mounted above the gas burner to         reflect heat downwards, and     -   a gas hose to supply gas from the gas tank to the gas burner         through the upright pole.

In a second aspect, there is provided a method for controlling gas supply to a gas burner of a patio heater, the method comprising:

-   -   setting a predetermined amount of time for gas to be supplied to         the gas burner; and     -   controlling the flow of gas from a gas tank to the gas burner;     -   wherein when the predetermined amount of time has not expired, a         closed and complete electrical circuit causes an         electromechanical valve to open and allow gas to flow from the         gas tank to the burner, and when the predetermined amount of         time has expired, the electrical circuit is opened to cause the         electromechanical valve to close and prevent gas flowing from         the gas tank to the gas burner.

BRIEF DESCRIPTION OF THE DRAWINGS

An example of the invention will now be described with reference to the accompanying drawings, in which:

FIG. 1 is a block diagram of a system in accordance with a preferred embodiment of the present invention; and

FIG. 2 is a front view of a control section of a system in accordance with a preferred embodiment of the present invention.

DETAILED DESCRIPTION OF THE DRAWINGS

Referring to FIG. 1, a patio heater gas control system 10 for controlling gas supply to a gas burner of a patio heater 20 is provided. The system generally comprises: a timing module 50 and an electromechanical valve 60. The timing module 50 is used for setting a predetermined amount of time for gas to be supplied to the gas burner. The electromechanical valve 60 controls the flow of gas from a gas tank to the gas burner. When the predetermined amount of time has expired, the timing module 50 opens an electrical circuit to cause the electromechanical valve 60 to close and prevent gas flowing from the gas tank to the gas burner.

An oxygen depletion system (ODS) 80 is provided to automatically extinguish and shut off the gas burner if the oxygen level falls below a predetermined level. The ODS is a safety device which activates a fires flame supervision device in any situation resulting in the presence of excessive levels of co² and carbon monoxide, which reduce the levels of oxygen causing the pilot flame to become unstable and lift off the thermocouple tip 70. The fire is then automatically turned off before the situation might become dangerous for people in the surrounding environment. The ODS 80 is a highly sensitive device to shut off a heating appliance if the oxygen level in an area falls below 18%. The standard oxygen level is 21%.

A tilt switch 40 is provided as another safety feature of the patio heater 20. If the patio heater 20 is accidentally knocked over and is non-vertical (more than 30° off the vertical axis), gas supply is automatically cut off to prevent a fire hazard.

A thermometer and thermostat 90 is provided to maintain a predetermined temperature. A user may set a predetermined temperature such as 25° C., and the thermometer monitors the temperature, and depending on the ambient environment will either maintain the current gas flow, increase the gas flow to increase the temperature or decrease gas flow to decrease the temperature accordingly.

An infrared remote control receiver 100 is provided to reset the predetermined amount of time for timing module. This allows a user to use a corresponding remote controller to control the temperature setting of the thermostat 90 and the timer 50 at a distance from the patio heater 20. The timing module 50 is a mechanical or an electronic timer. The electromechanical valve 60 is preferably a solenoid valve.

Generally, the patio heater 20 comprises: a base 21 to house the gas tank, an upright pole 22, the gas burner 23, a dome-shaped heat reflector 24 mounted above the gas burner 23 to reflect heat downwards, and a gas hose to supply gas from the gas tank to the gas burner through the upright pole 22.

The timer 50 functions as a circuit breaker. Electrical wiring 31 connecting the tilt switch 40 to the timer 50 to the solenoid valve 60 to the thermocouple tip 70 to the ODS 80 and back to the tilt switch 40 is able to form an electrical circuit. When the time remaining on the timer 50 has not expired, a closed and complete electrical circuit is formed which causes the solenoid valve 60 to be in an open state. When the solenoid valve 60 in the open state, the gas valve is opened and allows gas to flow from the gas tank to the gas burner. When the time on the timer has expired, the timer 50 causes the electrical circuit to become an open circuit which causes the solenoid valve 60 to change from the open state to the closed state. When the solenoid valve 60 is in the closed state, the gas valve to the gas tank is closed. Thus, when the time on the timer 50 has expired, gas is prevented from flowing to the gas burner which turns off the patio heater 20 safely and convenient without regular monitoring or user intervention.

Referring to FIG. 2, a control section 200 of the patio heater 20 is depicted. The control section 200 comprises written instructions on how to operate the patio heater 210, a control knob 220 to control the gas valve and ignition, and a timer knob 230 to set the time for the timer 50. In a typical scenario, operating the patio heater 20 initially requires turning the control knob 220 clockwise to the OFF position. Gas supply is provided by connecting the propane cylinder gas tank to a regulator inlet. Next, the timer knob 230 is turned to the ON position before ignition. To activate the timing function for the timer 50, the timer knob 230 is turned clockwise to the desired time setting (in minutes). The control knob 220 is pushed in slightly and turned counterclockwise to IGN/ON to ignite the gas burner. If ignition is unsuccessful at first, the control knob 220 is depressed and turned counterclockwise until the gas burner is ignited. The control knob 220 is remains depressed for at least 30 seconds after ignition of the gas burner. After 30 seconds has elapsed, the control knob 220 may be released. If the gas burner does not stay lit, the above steps may be repeated. When the burner is lit, the control knob 220 is turned counterclockwise to the desired temperature setting, for example, high, medium or low. When the time remaining on the timer 50 has expired, the gas supply is stopped and the control knob 220 returns to the OFF position. Although it has been described that the timer 50 opens an electrical circuit to cause the electromechanical valve to close and prevent gas flowing from the gas tank to the gas burner, it may modified to close and complete an electrical circuit if the solenoid valve 60 is also modified to respond accordingly.

It will be appreciated by persons skilled in the art that numerous variations and/or modifications may be made to the invention as shown in the specific embodiments without departing from the scope or spirit of the invention as broadly described. The present embodiments are, therefore, to be considered in all respects illustrative and not restrictive. 

1. A patio heater gas control system, the system comprising: a timing module to set a predetermined amount of time for gas to be supplied to a gas burner of the patio heater; an electromechanical valve to control the flow of gas from a gas tank to the gas burner; an oxygen depletion system (ODS) to automatically extinguish and shut off the gas burner if the oxygen level falls below a predetermined level; and a tilt switch to automatically extinguish and shut off the gas burner if the patio heater if it is tilted greater than a predetermined angle; wherein when the predetermined amount of time has not expired, a closed and complete electrical circuit causes the electromechanical valve to open and allow gas to flow from the gas tank to the burner, and when the predetermined amount of time has expired, the timing module opens the electrical circuit to cause the electromechanical valve to close and prevent gas flowing from the gas tank to the gas burner.
 2. The system according to claim 1, further comprising a thermometer and a temperature control module to maintain a predetermined temperature.
 3. The system according to claim 1, further comprising a remote control to reset the predetermined amount of time for timing module.
 4. The system according to claim 1, wherein the timing module is a mechanical or an electronic timer.
 5. The system according to claim 1, wherein the electromechanical valve is a solenoid valve.
 6. The system according to claim 1, wherein the patio heater comprises: a base to house the gas tank, an upright pole, the gas burner, a dome-shaped heat reflector mounted above the gas burner to reflect heat downwards, and a gas hose to supply gas from the gas tank to the gas burner through the upright pole.
 7. A method for controlling gas supply to a gas burner of a patio heater, the method comprising: setting a predetermined amount of time for gas to be supplied to the gas burner; and controlling the flow of gas from a gas tank to the gas burner; wherein when the predetermined amount of time has not expired, a closed and complete electrical circuit causes an electromechanical valve to open and allow gas to flow from the gas tank to the burner, and when the predetermined amount of time has expired, the electrical circuit is opened to cause the electromechanical valve to close and prevent gas flowing from the gas tank to the gas burner. 